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排序方式: 共有309条查询结果,搜索用时 15 毫秒
211.
Bieler M. Seitz S. Spitzer M. Hein G. Pierz K. Siegner U. Basu M.A. Smith A.J.A. Harper M.R. 《IEEE transactions on instrumentation and measurement》2007,56(2):266-270
The paper presents the results of the first intercomparison of the rise-time calibration of a 50-GHz sampling oscilloscope between Physikalisch-Technische Bundesanstalt, Germany, and National Physical Laboratory, U.K. (EUROMET project 641). Rise-times between 6.0 and 6.6 ps were obtained using optoelectronic techniques. Detailed uncertainty budgets are given, which yield typical rise-time uncertainties of 1.2 ps. The absolute values of the degree of equivalence are les 0.3 ps with an expanded uncertainty of 1.0 ps and, thus, validate the experimental techniques 相似文献
212.
通过对掩模衬底材料和掩模加工工艺利用硬性分界条件可满足45nm及以下技术节点的掩模要求。此外类似于折射指数、平整度、成分、均匀性和应力等衬底材料的固有特性严重地影响到掩模加工性能和光刻性能。评述了45nm及以下技术节点对空白材料,掩模及晶片层面的要求。指出了对于关键问题及出现的问题的可仿效实施的方法,最后研究了集成用于高效光掩模工厂的掩模材料的实际情况分析。 相似文献
213.
Ailén N. Rodríguez Mariana Escobar Ingrid E. Redersdorff Claudia A. Studdert Gustavo A. Abraham Pablo R. Cortez Tornello M. Karina Herrera Seitz 《应用聚合物科学杂志》2024,141(6):e54928
Polyhydroxyalkanoates (PHAs) are biopolymers accumulated by a diversity of bacterial strains as carbon and energy reserve when grown under unbalanced nutritional conditions. Among the wide spectrum of applications for these biopolymers, the generation of nano and microparticles has drawn huge attention. PHA nanoparticles showed a high surface-to-volume ratio that makes them interesting for pharmaceutical uses. Bacteria from the Halomonas genus became interesting tools for biopolymer production in the last years, due to its metabolic plasticity that allows them to grow in a wide spectrum of compounds and salt concentrations. Halomonas titanicae KHS3 was previously isolated based on their ability to grow using aromatic hydrocarbons as the sole carbon source. In this work, the novelty lies in the evaluation of PHA accumulation by H. titanicae KHS3. Accumulation was successfully observed and thoroughly characterized on various carbon sources. Irrespective of the carbon source employed for growth, our experimental conditions consistently yielded PHB as the sole material identified. The truly intriguing aspect of this study is that PHB solutions in glacial acetic acid demonstrated exceptional suitability for electrospraying processing. This groundbreaking development led to the creation of nanoparticles with unique characteristics that hold immense promise for a wide range of applications. 相似文献
214.
Janelle E. Jenkins Michelle E. Seitz C. Francisco Buitrago Karen I. Winey Kathleen L. Opper Travis W. Baughman Kenneth B. Wagener Todd M. Alam 《Polymer》2012,53(18):3917-3927
Solid-state 13C NMR experiments were performed on a series of linear poly(ethylene-co-acrylic acid) (E-AA) copolymers with the carboxylic acid group spaced precisely or randomly along the polyethylene backbone in order to determine the impact that molar percent acid content and acid group spacing have on the structure and dynamics of these materials. The impact of Zn-neutralization is investigated in precise E-AA ionomers. 13C cross-polarization (CP) NMR experiments with 1H dipolar or 1H spin-lock filters were utilized to identify the amorphous or crystalline components in the materials. Constraints extracted from the filtering experiments were used to fit quantitative NMR data for samples that contained both crystalline and amorphous regions. All random copolymers contained crystalline phases, while only the precise sample with the longest polyethylene run between acid groups (twenty CH2 groups) contained a crystalline component. The crystalline phase in this precise copolymer decreased with increasing zinc content. 相似文献
215.
A Bornscheuer KH Mahr KJ Oldhafer M H?ltje M Szabo SK Kirchhoff W Seitz E Kirchner 《Canadian Metallurgical Quarterly》1997,22(5):116-120
The isolated hyperthermic liver perfusion with mitomycin C presents a new technique of regional therapy for irresectable liver tumours. The advantage is a high local concentration of the antitumour agent with reduced systemic side-effects. Isolated hyperthermic liver perfusion is an extensive surgical procedure requiring a veno-venous bypass and a heart-lung machine. Disturbances affecting the base-acid hemostasis, the coagulation system and the cardiocirculatory function can occur. To date, there has been little experience with this technique. The intraoperative changes during the isolated hyperthermic liver perfusion in our series were similar to those seen during orthotopic liver transplantation. In contrast to orthotopic liver transplantation, heparin is given during the anhepatic phase. The reperfusion after isolated hyperthermic liver perfusion was not complicated by severe cardiocirculatory changes. A decrease in body temperature was not observed probably due to the absence of cold, potassium-rich perfusate flowing into the systemic circulation. Two patients developed signs of a reperfusion syndrome within the first hour after reperfusion (decrease in peripheral systemic resistance). 相似文献
216.
217.
Stalk synthesis in Caulobacter crescentus is a developmentally controlled and spatially restricted event that requires the synthesis of peptidoglycan at the stalk-cell body junction. We show that the beta-lactam antibiotic mecillinam prevents stalk synthesis by inhibiting stalk elongation. In addition, mecillinam causes an increase in the diameter of the stalk at the stalk-cell body junction. We describe two mutations that confer resistance to mecillinam and that prevent stalk elongation. These mutations are probably allelic, and they map to a locus previously not associated with stalk synthesis. 相似文献
218.
M Lebech DH Joynson HM Seitz P Thulliez RE Gilbert GN Dutton B Ovlisen E Petersen 《Canadian Metallurgical Quarterly》1996,15(10):799-805
Classification systems and case definitions provide the foundations upon which clinical and epidemiological studies are based. The European Research Network on Congenital Toxoplasmosis acknowledged the lack of such a system or definitions within its field of interest and established a working group to address the issue. Congenital Toxoplasma gondii infection was defined as occurring in four separate patient groups: pregnant women, fetuses, infants, and individuals > 1 year of age. The likelihood of Toxoplasma gondii infection was separated into five mutually exclusive categories: definite, probable, possible, unlikely, and not infected. Inclusion within a specific category is dependent upon the case definition, which is in turn derived from criteria based on serological, parasitological, and clinical information. Notes are included within the classification not only to clarify the definitions, but also to improve the reliability and quality of diagnosis. The goal is to construct a system that encompasses all aspects of congenital toxoplasmosis, which is applicable to different countries and health services, suitable for large epidemiological studies, aids the diagnosis and management of individual cases, and lends itself to computerisation. 相似文献
219.
We present a novel approach to the robust classification of arbitrary object classes in complex, natural scenes. Starting
from a re-appraisal of Marr's ‘primal sketch’, we develop an algorithm that (1) employs local orientations as the fundamental
picture primitives, rather than the more usual edge locations, (2) retains and exploits the local spatial arrangement of features
of different complexity in an image and (3) is hierarchically arranged so that the level of feature abstraction increases
at each processing stage. The resulting, simple technique is based on the accumulation of evidence in binary channels, followed
by a weighted, non-linear sum of the evidence accumulators. The steps involved in designing a template for recognizing a simple
object are explained. The practical application of the algorithm is illustrated, with examples taken from a broad range of
object classification problems. We discuss the performance of the algorithm and describe a hardware implementation. First
successful attempts to train the algorithm, automatically, are presented. Finally, we compare our algorithm with other object
classification algorithms described in the literature. 相似文献
220.
An efficient image compression/decompression technique for complex scenes is presented. An image is first decorrelated by a full two-dimensional DCT (discrete cosine transform). The resulting coefficient map is weighted using properties of the human visual system and finally encoded with a novel multiresolution encoder. The result is converted into printable ASCII for transmission by electronic mail 相似文献